DC arc lamps such as a xenon arc lamp requires a very brief high voltage pulse, typically 20 kV or higher, to create an initial ‘streamer’ of ionized gas between the cathode and anode of the lamp. This creates a conductive path of charge-carrying ions. Following this pulse, and before the ionization naturally decays due to recombination of ions, the direct current supplied to the lamp, at low voltage, must be ramped up quickly, but in a controlled manner. This increasing current sustains the ionization and develops the initial streamer into a full scale arc. Once the full arc is achieved, the lamp is supplied in a constant-current mode, to ensure stable operation and to avoid over-driving the lamp.
It is highly desirable, in many critical applications, that lamps ignite 100% reliably each time that ignition is attempted. Conventional starting circuits, however, allow only a brief interval between the cessation of the high voltage pulse and the initiation of the current ramp up. This is primarily due to the inductance in the ignition pulse generating circuit, which conventionally employs a transformer that slows the rate of increase in current. This delay may cause intermittent misfiring of the lamp causing the lamp to not ignite 100% of the time.
Accordingly what is needed is a simple and reliable starting circuit for arc lamps such as Xenon arc lamps that reliably ignites the lamp 100% of the time.
It is important to note that the present invention is not intended to be limited to a device or method which must satisfy one or more of any stated or implied objects or features of the invention. It is also important to note that the present invention is not limited to the preferred, exemplary, or primary embodiment(s) described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the allowed claims and their legal equivalents.